This invention relates to a locking system comprising a male cylindrical end of a first element and a female tubular cylindrical end of a second element, the male cylindrical end being intended to be engaged inside the female tubular cylindrical end to couple the first element to the second element.
Many locking systems exist for coupling and locking two mechanical elements such as a tool and a tool holder, the tool and its tool holder being with corresponding cylindrical male (in general for the tool) and female (in general for the tool holder) ends. The tool can be for example a cutting or sharp tool, a screwdriver, a mechanical key, a drill, a tap, etc. The locking system used is then for example with a mandrel, tightening screw, clamp, using a system for tightening with or without a return spring. It generally has a certain complexity, in particular in terms of ergonomics and usage, requiring the two hands of a user and sometimes the use of a screwdriver or specific locking keys.
Many locking systems also exist for coupling and locking two mechanical elements such as coaxial cables or ducts of which the ends are also of corresponding male and female shapes. They also generally have a certain complexity and must further provide a good seal (fluidic transmission ducts) or a good connection (electrical cables). These seal and connection constraints can also apply to certain precision tools, in the medical field for example. They participate in the complexity of the locking.
It is desirable despite everything, in particular in precision applications, to simplify the ergonomics of the lock. The invention then applies more particularly to a locking system of the aforementioned type, wherein:                a locking groove is hollowed in the outer surface of the male cylindrical end,        the female tubular cylindrical end is bored on the side with a through-opening inside of which is arranged a mobile locking element able to protrude inside the female tubular cylindrical end in the locking groove of the male cylindrical end, and        a locking ring is mounted on the outer surface of the female tubular cylindrical end opposite the through-opening, with this ring having an inner surface wherein a recess with variable depth enables the locking/unlocking of the mobile locking element against the locking groove depending on the position of the ring.        
Such a locking system is for example described in the French patent published as number FR 2 707 432 B1. In this document, an annular locking groove is hollowed in the outer surface of the male cylindrical end. The mobile locking element is a ball and, according to the axial position of the locking ring along the female tubular cylindrical end, the inner surface of the locking ring being itself also provided with one or several annular grooves, the ball is compressed and blocked against the locking annular groove or unblocked. More precisely, the ball is blocked against the locking groove of the male cylindrical end when the latter is arranged opposite the through-opening and when the ball is not opposite one of the annular grooves of the female tubular cylindrical end; on the contrary, the ball is unblocked with a certain degree of freedom when it is opposite one of the annular grooves of the female tubular cylindrical end.
The ergonomics of this locking system is improved as compared to the other existing systems, but the system remains complex, in particular because it requires providing return means and also because certain actions of locking or unlocking, according to the embodiment chosen, can require axial movements in opposite directions to be carried out at the same time wherein the two hands of a user must then be solicited.